Taking the advise of a few people, I finally set out to figure out why my one inch keyed hub fits so loosely on the motor shaft. Let me remind you that in a previous post, I blamed Princess Auto for what I assumed was a poor quality, mis-machined part.
Out came my 0-1" micrometer and inside bore gauge. It turns out that the Princess auto piece is exactly one inch ID. It also turns out that the motor shaft is .982" OD. What this means, ladies and gentlemen, is that the shaft is not one inch in diameter, but 25mm. I didn't know they came in metric sizes. Back to the drawing board.
I am going to ship the whole thing to my friend Matt (a machinist) by the weekend - motor, a new 7/8" hub (that he can lathe out to fit the motor shaft. Wait, didn't I return one of those already?!) and clutch center. When he is finished, it will definitely work. So again I wait.
My apologies to Princess Auto. I will never doubt you again.